JPS5942107B2 - Artificial leather and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel artificial leather and a method for producing the same.

Leather-like materials generally used as artificial leather have a base material of nonwoven fabric or knitted fabric, and are filled with a rubber-like elastic polymer.

Conventionally, the nonwoven fabric used as a base material for these materials is made by forming staples of various natural fibers, recycled fibers, synthetic fibers, etc. into a sheet-like material by carding, cross layering, random univer, etc., and then entangling them by needle punching. It is generally made by

However, since the staples used in this case are ordinary staples, only staples with very different properties compared to natural leather can be obtained.

Attempts have been made to solve these problems and make the structure similar to that of natural leather.

That is, Japanese Patent Publication No. 44-24699 describes a nonwoven fabric mainly composed of fiber bundles obtained by bundling a large number of single fibers.

The nonwoven fabric proposed in Japanese Patent Publication No. 44-24699 is made by applying glue to a fiber bundle made of a large number of single fibers to maintain the unity, cutting it into a certain length and making it into a web, which is then bonded by needling. The sizing agent that was used to hold the fiber bundles was applied and then treated with a different type of binder from the sizing agent used when making the fiber bundles, and then the sizing agent that held the fiber bundles was removed by finishing treatment.

Such a nonwoven fabric is extremely flexible because the constituent single fibers within the fiber bundle are mutually free.

However, this nonwoven fabric is too soft and has a paper-like texture with a loose lid, so it cannot currently be used in fields such as outerwear.

In order to improve this drawback, if the voids in the nonwoven fabric are filled with a rubber-like elastic polymer such as polyurethane, the nonwoven fabric will have an appropriate hardness.

However, since the prefabricated nonwoven fabric is too flexible, a relatively large amount of rubber-like elastomeric polymer must be used to achieve the appropriate hardness, in which case the resulting leather-like material It has the disadvantage that it has a rubber-like, loose texture and a hard texture with a core.

The present invention solves these problems by using non-woven fabrics or knitted fabrics in which the adhesive strength between single yarns is adjusted to various strengths as a base material, and using rubber-like elastic polymers used for this purpose. By appropriately selecting the amount, it was possible to obtain a leather-like material with a texture that closely resembles natural leather, neither too soft and limp, nor too hard and rubber-like with a loose core. The product of the present invention has excellent physical properties and can have a wide range of textures, from soft with moderate firmness and firmness to highly elastic with no core. It has the advantage of being able to provide leather-like products suitable for various uses, and is very useful not only for clothing but also for upper leather.

That is, the present invention relates to a nonwoven fabric or a knitted fabric made of long fibers or short fibers formed from a fiber bundle that is composed of a large number of ultrafine single yarns of 0.005 to 0.5 denier and in which the single yarns are self-adhered to each other. The present invention relates to a leather-like material having a structure in which a rubber-like elastic polymer is filled between the structural tissues of the structure.

The present invention will be explained in detail below.

The leather-like material obtained by the present invention has a structure very different from that of conventionally known artificial leather.

That is, the leather-like material according to the present invention has a content of 0.005 to 0.5
It is made up of fiber bundles in which ultra-fine single fibers called denier are self-adhered to each other, and the fiber bundles can be knitted or tightly intertwined to form non-woven fabrics.

A space formed by the intertwining of fiber bundles forming the nonwoven fabric or the knitted structure is filled with a rubber-like elastic polymer, such as polyurethane.

As described above, the characteristic feature of the leather-like product according to the present invention is that, in terms of structure, the single fibers of fibers other than copper ammonia rayon that constitute the base material are self-adhered to each other, and by using an adhesive, The reason is that it is not made by bonding single fibers together.

Next, a method for producing a leather-like article having the above structure will be explained in detail.

First, in order to obtain a self-adhesive fiber bundle composed of ultrafine single fibers with a fineness of 0.005 to 0.5 deniers, for example, in the case of recycled fibers such as viscose rayon, spun 0.005 to 0.5 deniers are used. When ultrafine 5-fibers of 0.5 denier are regenerated and coagulated in water, when they are focused by a semi-solidified focusing guide, the single fibers self-adhere to each other to form a fiber bundle.

In addition, in order to spin single fibers in an extremely fine state of 0.005 to 0.5 denier, it is possible to spin them by adjusting the extrusion amount of the stock solution, the diameter of the spinning holes, etc. is in a semi-solidified state (a large number of single fibers are self-adhered to each other, 1 to 2
Since the fiber bundle is approximately 0.00 denier, problems such as single fibers breaking during spinning are unlikely to occur.

On the other hand, in the case of synthetic fibers such as polyamide, 0.005
There is also a method of extruding a large number of single fibers of ~0.5 denier from a spinneret, but synthetic fibers need to be drawn afterwards, which has the disadvantage that thread breakage and single fiber breakage are likely to occur during this process.

To avoid this, there is a well-known method of spinning and drawing sea-island fibers and removing the sea component afterwards.

This method is disadvantageous because the process is complicated, but it does not cause single thread breakage.
Problems such as thread breakage can be avoided.

By exposing the ultrafine single fibers thus obtained to superheated steam at a temperature of about 130 to 200°C, depending on the running speed of the fiber bundle, the single fibers self-adhere to each other.

In this case, a method of heating at a temperature higher than the melting point of the polyamide may be considered, but this method is not preferred because it exceeds the level of self-adhesion and ends up completely fused.

The strength of the bond can be varied, for example by changing the position of the focusing guide or the degree of focusing in the case of recycled fibers.

In other words, it changes depending on whether the particles are focused when they are barely solidified or whether they are focused in a state where the solidification has progressed considerably.

Alternatively, it also depends on whether the focus is strongly focused or relatively weakly focused.

In the case of polyamide, it can also be changed by the temperature of steam or the state of convergence, as in the case of recycled fibers.

It also varies depending on the speed at which the fiber bundle passes through the heating zone.

The self-adhesive fiber thus obtained can have any degree of adhesion depending on preference.

The degree of adhesion of such self-adhesive fibers is such that even the strongest fibers are such that the single threads will come apart when rubbed vigorously by hand.

The self-adhesive fiber bundle referred to in the present invention refers to a bundle in which a large number of single fibers are self-adhered to each other along the longitudinal direction of the fibers, even if they are not completely adhered along the longitudinal direction. Often, it may be partially glued.

FIG. 1 shows a cross section of a self-adhesive fiber bundle, and the part A in the figure is the adhesive part.

Figures 2 and 3 are diagrams showing the state of adhesion in five directions of a self-adhesive fiber bundle. Figure 2 shows a case in which single fibers are completely self-adhered to each other, and Figure 3 shows a case in which the single fibers are partially self-adhered. The adhesive has come off.

In the present invention, the self-adhesive fiber bundle thus obtained is made into a nonwoven fabric or knitted fabric while maintaining the fiber bundle state, and is combined with a rubber-like elastic polymer to form a leather-like product.

When the long fibers are made into a non-woven fabric, the self-adhesive fiber bundles are dropped onto a wire mesh using the force of water or air.

When making a non-woven fabric in the form of short fibers, a large number of fiber bundles are collected into a tow, crimped by a method such as a pressing method, and then cut and stabilized, and the resulting fabric is made into a tow. This can be carried out by separating the fibers into individual fiber bundles and forming them into a wrap shape, then forming them into a sheet shape by cross layering, random univer, etc., and intertwining them by means such as needle punching.

In addition, in order to make a knitted fabric, the long fiber bundle can be made into a knitted fabric using a normal knitting machine or a loom. Filled with a rubber-like elastic polymer, for example, a nonwoven or knitted fabric is impregnated with a dimethylamide solution of polyurethane, and then the nonwoven or knitted fabric is placed in water to solidify the polyurethane. It is.

The feature of the leather-like product according to the present invention is that the base material is a knitted fabric or a non-woven fabric consisting of fiber bundles made up of a large number of ultrafine single fibers of o, oo 5 to 0.5 deniers and self-adhered to each other. , it is extremely flexible compared to a leather-like material made of a knitted fabric or non-woven fabric made of a single fiber of the same denier as the self-adhesive fiber bundle, and a large number of ultra-fine single fibers do not self-adhere to each other. Unlike leather-like materials based on knitted fabrics or non-woven fabrics made of aggregated fiber bundles, which are flexible but have a lidded and stiff paper-like texture, fabrics that are flexible and have moderate stiffness and burr. The point is that you can obtain a unique texture.

Furthermore, by controlling the degree of adhesion of the self-adhesive fiber bundles, we can create a texture that is flexible and has just the right amount of waist and width.
Another feature of the present invention is that it is possible to obtain textures with a variety of textures, from coreless hardness to textures rich in elasticity.

Another feature of the invention is that it is simple to manufacture.

In the present invention, a non-woven fabric or a knitted fabric is first made from a large number of ultra-fine fiber bundles. At this time, when self-adhesive fiber bundles are used as in the present invention, the fibers behave in the form of a bundle, making it easy to make. The desired nonwoven fabric can be obtained.

Furthermore, it is convenient because troubles such as single thread breakage that occur during the process can be avoided.

Furthermore, the present invention does not use any other material to bond the large number of ultrafine fibers, thereby avoiding the complicated process and the complexity of eluting them later. can.

Furthermore, if the single fibers are bonded together using an adhesive and the adhesive is not eluted afterwards, only a very hard product will be obtained.

The leather-like article according to the present invention can be made through various processes and their modification processes.

The spunbond method using long fibers, the dry short fiber method (curd, random uniform, needle punch, etc.), and the wet short fiber method (papermaking method) are common methods for manufacturing the nonwoven fabric used in the present invention.

If the leather-like material according to the present invention has a strong adhesive strength and is hard, it can be made soft by reducing the degree of adhesion of the self-adhesive fiber bundle by rolling it.

It can also be made softer by repeated washing.

The fineness of the single fibers of the self-adhesive fiber bundle used in the present invention is 0.
．． 005 to 0.5 denier is used,
Particularly preferred is one with a denier of 0.01 to 0.2.

If it is less than 0.005 denier, the fiber strength becomes too weak,
If it exceeds 0.5 denier, the suppleness characteristic of leather-like materials will be lost.

The fiber bundle used has a denier of 1 to 200 deniers, but the optimum denier of the fiber bundle varies depending on the manufacturing process or the intended leather-like material.

For example, in the case of a dry short-fiber nonwoven fabric, the denier is preferably 1 to 30 deniers from the viewpoint of processability of carding and needle punching, and the density of the nonwoven fabric.

Even when making a nonwoven fabric using a fiber bundle of long fibers, the density of the nonwoven fabric is preferably 1 to 30 deniers.

In the case of knitted fabrics, it is preferably 30 to 200 deniers in view of processing operability and density of the knitted fabrics.

As the rubber-like elastic polymer used in the present invention, any polymer having rubber-like elasticity that has been conventionally used for artificial leather can be used.

For example, synthetic rubber such as polyurethane, NBR, SBH,
Homopolymers such as polyvinyl chloride, acrylic acid polymers, amino acid polymers, and copolymers thereof can be used.

Generally, the rubber-like elastic polymer can be filled by impregnating a nonwoven fabric or knitted fabric made of long or short fibers with an emulsion or latex solution of the polymer.

As the fiber material in the present invention, recycled fibers, synthetic fibers, etc. other than cuprammonium rayon can be used. Specifically, viscose rayon, acetate, nylon, polyacrylonitrile, polyethylene, polypropylene, etc. can be used.

In the present invention, it is of course possible to use applied techniques conventionally used in the production of artificial leather.

For example, a thick non-woven fabric can be made in advance and then sliced to the desired thickness, the surface can be puffed to give it a suede or velor effect, or a highly concentrated polyurethane solution can be applied to the surface and then coagulated to give silver. The method for forming a surface layer is to puff the knitted fabric in advance, or to make a knitted fabric with loops, cut it to expose many fiber ends, impregnate it with a polyurethane solution, solidify it, and then puff it. method, and various other methods can be adopted.

Hereinafter, the present invention will be further explained in detail with reference to Examples and Comparative Examples.

The evaluation values in the examples are values measured by the following method.

1. Flexibility: JIS L-109645°
The value measured based on the cantilever method is an index expressing flexibility, and the smaller the value, the more flexible it is.

2. Wrinkle resistance: Value measured based on JIS L-1096 wire method In the case of the present invention, this value was used as an index expressing elasticity.

The higher the value, the firmer and firmer the texture and the firmer and more elastic the texture.

Example 1 Viscose rayon stock solution was extruded into dilute sulfuric acid and spun into a single fiber having a fineness of 0.1 denier through a 300-hole spinneret, and when it was in a semi-solidified state, it was bundled with a focusing guide,
The single fibers were allowed to self-adhere to each other and then completely coagulated and rolled up.

The obtained fiber bundle was composed of 300 single fibers of 0.1 denier and had a total fineness of 30 denier.

Apply polyvinyl alcohol to this fiber bundle at a rate of 3% per fiber bundle.
After attaching the weight, 400 fiber bundles were collected into a tow, crimped by the pressing method, and then 50 mm thick.
It was cut to length and made into a fabric.

This fabric was defibrated into fiber bundles using a card machine, then cross layered and needle punched to form a nonwoven fabric.

The basis weight of this non-woven fabric is 450g/7? It was Z2.

Next, it was immersed in 10% polyvinyl alcohol, squeezed with a mangle, and dried at 100°C.

This material is immersed in a dimethylformamide solution with a weight ratio of 20% polyurethane, squeezed with a mangle, and then the weight ratio is 50%.
The polyurethane was slightly coagulated by immersion in a 150% water/dimethylformamide solution.

The polyurethane was then squeezed with a mangle and poured into water to completely solidify the polyurethane.

Only the surface was sliced and smoothed using a slicer.

Finally, when polyvinyl alcohol was extracted during diving, a leather-like material with no core and a hard, elastic texture was obtained.

Its hardness was comparable to that of cowhide leather used in Chinese products.

A dimethylformamide solution of 25 parts by weight of polyurethane was applied to this material using a reverse coater and coagulated in water to obtain an artificial leather with a silver surface layer.

This item was as follows.

Polyurethane/Non-woven fabric 60/40 mesh 7009
/rr? Thickness 1.
7mm tensile strength 0.50 Kg/my
? Elongation: 70 Softness (Cansiver method): 118 mm Wrinkle resistance: 95 Example 2 Viscose rayon stock solution was spun into dilute sulfuric acid through a 100-hole spinneret so that the fineness of the single fiber was 0.1 denier. , when in a semi-solidified state, the fibers were focused by a focusing guide and the single fibers were self-adhered to each other.

This fiber bundle was composed of 100 single fibers of 0.1 denier, and the total fineness was 10 denier.

This fiber bundle was dropped together with water onto an endless rotating wire gauze without being rolled up to form a sheet-like product.

Next, it is impregnated with a 3 weight width aqueous solution of polyvinyl alcohol,
It was squeezed with a mangle and then dried.

Next, 3000 pieces/1 nch were needled using a needle punch machine.

The effect of the needle punching performed in this example is completely different from that on short fiber nonwoven fabrics made from ordinary textiles.

The former was carried out to cut the fiber bundle and facilitate puffing in the subsequent process, while the latter was carried out primarily to entangle the fibers three-dimensionally and increase their density.

The sheet-like material obtained in this way is again impregnated with a polyvinyl alcohol solution of 3 weight width, then the surface is rubbed with a brush, the cut fiber bundles are oriented in a certain direction, and after being squeezed very lightly with a roller, a suction drum Excess polyvinyl alcohol was removed by drying.

Next, this material was impregnated with a 10 weight width polyurethane/dimethylformamide solution, squeezed with a mangle, and then poured into water to solidify the polyurethane.

After drying, a suede-like leather-like material was obtained by puffing.

This one showed the following data.

Polyurethane/non-woven fabric 30/70 mesh 250.
9/rr? thickness
1.1 Tensile strength 0.60 Kq/m
m'' Tensile elongation: 38 Softness (cone angle bar method): 82 m 11 L Wrinkle resistance: 93 Comparative Example 1 A nonwoven fabric with a single yarn of 0.1 denier and a fiber bundle of 10 denier was prepared in the same manner as in Example 2. .

However, since the fiber bundle was not focused by the focusing guide, it did not self-adhere.

This fiber bundle was dropped together with water onto an endless rotating wire mesh without winding it up, but as soon as it collided with the wire mesh, the fiber bundle split into single fibers and fell apart, making it impossible to obtain the desired nonwoven fabric made of fiber bundles. There wasn't.

Example 3 Viscose rayon raw material i1 [W] Spun into dilute sulfuric acid from a 100-hole spindle so that the fineness of single fibers was 0.2 denier, and spun each 100-hole spindle when in a semi-solidified state. Each fiber was bundled using a focusing guide to obtain a self-adhesive fiber bundle with a total fineness of 20 denier.

A large number of fiber bundles obtained in this manner are collected into a tow, impregnated with a 3-weight width methoxylated methyl nylon/methanol solution, dried, and then pressed into a tow with 12 threads/1.
The fibers were crimped and cut into 5 cm lengths to make fiber bundles.

170g/? of this soup by card, cross layer, needle punch? After forming a 7Z2 nonwoven fabric, it was immersed in a 20 weight width polyurethane/dimethylformamide solution, squeezed with a mangle to various squeezing ratios, and then coagulated in water.

The methoxylated methyl nylon was then dissolved by immersion in boiling methanol for 10 minutes.

After drying, the surface was puffed to obtain a suede-like leather-like material.

The resulting leather-like materials were as follows, depending on the amount of polyurethane deposited.

Comparative Example 2 A fiber bundle having a single yarn of 0.2 denier and a total fineness of 20 denier was obtained in the same manner as in Example 3.

However, this time I did not focus it with a focusing guide and did not self-adhere it.

The obtained fiber bundle was immediately coated with 0.5% methoxylated methyl nylon without being rolled up.

During this process, fuzzing of single yarns and breakage of fiber bundles occurred frequently, and the work was not in a satisfactory state.

After collecting relatively good fiber bundles and forming them into tows, crimping them by pressing, cutting them into lengths of 5CW1 to make fabrics, guarding, cross-layering, and needle-punching the fibers to 1709/rr. It was made into a non-woven fabric.

Thereafter, leather-like products were obtained in the same manner as in Example 3, but the properties of the products differed as follows due to the difference in the amount of polyurethane deposited.If the amount of polyurethane was small, the texture was similar to that of cloth and it was too soft. , when the amount of polyurethane was increased, it became rubber-like.

Example 4 Polystyrene/nylon 6 of 50150 was blended in the form of chips, then melt-mixed and spun using an extruder equipped with a static mixer and drawn using a drawing machine to obtain a drawn yarn of 15 denier/1 filament.

This drawn yarn was introduced into heated trichlorethylene to dissolve the polystyrene, and then the obtained ultrafine fiber bundle was exposed to superheated steam at 150° C. to cause self-adhesion.

The speed of the fiber bundle was 100 m/min. The self-adhesive thread thus obtained was dropped onto a wire mesh using the force of air.
509/rr? A long fiber nonwoven fabric was obtained.

This was impregnated with a 20 weight polyurethane/dimethylformamide solution and then placed in water to coagulate the polyurethane.

Next, a thin layer of 28wt polyurethane/dimethylformamide was applied using a reverse coater and coagulated in water.

The obtained leather-like material was a supple leather-like material with grainy bones, and was as follows.

Polyurethane/non-woven fabric 60/40 mesh 650g/
? ? Z2 thickness 1.
6 Tensile strength 0.75 Kqlmm”
Tensile elongation: 65% Flexibility (cantilever method): 118mm Wrinkle resistance
Example 5 of Section 97 A self-adhesive fiber bundle of 200 denier nylon 6 obtained in the same manner as in Example 4 was knitted smoothly using a knitting machine.

The obtained knitted fabric was immersed in a 10 weight polyurethane/dimethylformamide solution and then placed in water to coagulate.

When the obtained product was rubbed with sandpaper, the surface became fluffed, and a soft and moist product was obtained.

The resulting product was a leather-like material suitable for outer clothing, although the stitches remained and it was very different from that made from non-woven fabric.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a cross section of a self-adhesive fiber bundle. Figures 2 and 3 are diagrams showing the state of adhesion in the longitudinal direction of self-adhesive fiber bundles. Figure 2 shows one in which the single fibers are completely self-adhered to each other, and Figure 3 shows one in which the single fibers are partially adhered. is peeled off. In the figure, part A is the adhesive part. ;1[

Claims (1)

[Claims] 1 0.005 to 0.5 other than copper 7 ammonia rayon
The structure of a non-woven or knitted fabric structure made of long fibers or short fibers, which is composed of a large number of single fibers of denier, and which are formed by fiber bundles that are bonded to each other in h''-6 distribution. Artificial leather with a structure in which a rubber-like elastic polymer is filled between tissues. 2 0.005 to 0.5 other than copper 7 ammonia rayon
A large number of single fibers of denier are self-adhesive to form a self-adhesive fiber bundle, and then the self-adhesive fiber bundle is used while maintaining the fiber bundle state to form a structure of non-woven fabric or knitted fabric, and rubber is inserted between the structural tissues of the structure. A method for producing artificial leather, characterized by filling it with a shaped elastic polymer.